Mechanical pencil



March 8, 1938.

R. E. FRIEDLEIN Er Al.

MECHANICAL PENCIL Filed Dec. 1o, 193s W M mi w Nw@ ma wwf o m5 mw /ll l lPaaenw1.Mar.8, 193s MECHANICAL PENCIL Robert E. Friedlein, Mountain View, N. J., and

` David Juelss, Brooklyn, N. Y., assignors to The American Lead Pencil Company, Hoboken, N. a corporation of New York Application December 10, 1935, Serial No. 53,692

4 Claims.

'This invention relates to mechanical pencils and particularly to improvements therein and ln the feeding mechanism thereof.

An object of the invention is the provision of a pencil of simplev and inexpensive construction which is adapted to receive a long lead and to propel or withdraw the lead as may be desired.

Another object of the invention is the provision of means to expel the end of the lead when it is substantially used up in order that a new lead may be inserted.

A further object of the invention is the provision of a simple and eiiective clutch mechanism which permits the operation of the propelling means but prevents breakage of the l delicate mechanism by continued turning thereof after the parts have reached one or the other end of their path of travel.

f Other objects and 'advantages of the invention will be apparent as it is better `understood by reference to the .following specification and the accompanying drawing, in which Fig. 1 is a longitudinal section through a. pen.

Figs. 4 and 5 are details in perspective of parts of the propelling mechanism. K

Referring to the drawing, the pencil may comprise any suitable form of casing 5 which may be made of metal or any other suitable material. A terminal conical section 6 of the casling is rigidly secured thereto to form the point of the pencil and is made also of metal or other suitable material.

Within the casing 5, a tubular member 1 having a longitudinal slot 8 is rigidly supported on the terminal conical section and is supported thereby. Loosely mountedron.' the tubular member 1 between washers 9 /and 'III is a helical propelling member II which is secured in position under compression by ai washer I2 above the washer I and adapted tothe engaged by an expanded section I3 of the` tubular memberl 1. Thus, the several parts are held in assembled relation, the compression of the helical member` I I being adapted to afford rigidity and to prevent looseness or wabbling of the lead as the latter 'is used.

The lead-advancing mechanism comprises a tubular slotted member I4 disposed within the tubular member 'I and having ears "I5 which are adapted to embrace the helical memberA Ii so that as the latter is rotated the tubularcasing Irl is advanced or withdrawn. Within the tubular member It a plunger IIiis supported with ears il likewise adapted `to embrace the helical member Il. The lead I8 is inserted'through an opening in the end of the pencil and into the end of the tubular member I4 bearing against the `end of the plunger it. Consequently the ro' tation of the helical member I I engaging both the tubular member It and the plunger I causes the lead to advance when', the 'helical member is rotated in one direction and. since the end of the lead is gripped by the tubular member ifi, to withdraw the lead when the hell cal member at the section having the coarser pitch. However,` as the downward movement of the lead I8 results nally in using all but a relatively short portion thereof, the movement of the tubular member I4 is retarded by engagement .with the section of the helical member of shorter pitch and the plunger I6 is advanced relatively to the tubular member Il to the position indicated in Fig. 2 of the drawing, at which point the end of the lead is expelled. By reversing the movement of the parts, the tubular member III and the plunger I6 may be withdrawn and a new lead may be inserted.

To effect the movement of the helical member II, a collet or spring clutch member I9 is supported beneath the fibre washer III surrounding a portion of the helical member I I. The collet is slotted at 20 on opposite sides to afford a vdegree of resilience, and the opposite parts when forced inwardly are adapted to grip the helical memberl I. A tubular member 2l, which may carry a head 22 supporting an eraser 23, if desired, is adapted to be inserted between the casing 5 and the collet -I 9, the parts being so proportionedthat the collet is thus forced into engagement with the helical member II`. Rotation of the tubular member 2l ineither direction thus-imparts the desired movement to the helical member 11 tov advance or retract the lead through the mecha` nism hereinbefore described. Should the parts of the mechanism be at either end of the path of travel, continued rotation of the tubular member 2| will result merely in slippage through the frictional connection, and the pencilv will not be damaged. The clutch mechanism is nevertheless sufficiently positive in operation to ensure the satisfactory operation of the pencil, that is to say, the lead may be advanced or retracted readily and atwill. i

The structure as described is simple, inexpensive and effective, but various changes may be made therein Without departing from the invention or sacriiicing any of the advantages of the structure.

We claim:

l. A pencilcomprising a casing, a helix within the casing, guide means fixed relative to the casing, lead carrying means guided by the guide means and engaging the helix and actuated by the rotation thereof to advance or retract, and clutch means for moving the helix including a resilient slotted collet surrounding a portion of the helix and cylindrical means rotatable in and extending from the casing adapted to engage and compress the collet.

2. A pencil comprising a casing, a wire helix within the casing, means for holding the helix under compression, guide means .xed relative to the casing, lead carrying means guided by the guide means and engaging the helix and actuated by the rotation thereof `to advance or retract, and clutch means for moving the helix including a. resilient slotted collet surrounding a portion of the helix and cylindrical means rotatable in and ex- A tending from the casing-adapted to engage and compress the collet.

3. A pencilcomprising a casing, a helix within able in and extending from the casing adapted to engage and compress the collet.

4. A pencil including a plurality of relatively rotatable means, one of said means comprising a helix, the other of said means comprising a guide, lead-carrying means guided by the guide for movement upon relative rotation of the rotatable means, and clutch means for engaging one of said rotatable means to rotate the same relative to the other rotatable means, said clutch means including a slotted collet, and means for 

